Hmm, if it wasn't lifted I would say that's a possibility. With it being lifted I'll bet you are experiencing "axle wrap" under hard acceleration, especially if it's just lifted with blocks and not new springs. You might want to invest in actual rear springs and possibly ladder/traction bars. This should help eliminate axle wrap. Axle wrap can be very hard on the driveshaft and u-joints also.
Never mind, I see you say springs and blocks. With that much lift traction bars are going to definitely be needed.